Rock drill



Dec. 17, 1940. G AR -IN 2,225,588

nocx DRILL Original Filed March 6, 1934 3 Sheets-Sheet 1 E.G.GARflN ROCK DRILL Deb. 17, 1940.-

Original Filed March 6, 1934 3 Sheets-Sheet 3 142mm Z04 ZEYZWW fmeiin.

AQJMMW Q E m Patented Dec. 17, 1940 UNITE STATES PATENT OFFICE ROCK DRILL Massachusetts Application March 6, 1934, Serial No. 714,315 Renewed May 1'7, 1939 32 Claims.

This invention relates to rock drills, and more particularly, but not exclusively, to imp-rovements in the feeding mechanism of such drills.

An object of this invention is to provide an improved rock drill. Another object is to provide an improved rock drill feeding mechanism. A further object is to provide an improved feeding mechanism for a rock drill of the mounted drifter type. Yet another object is to provide an improved pneumatic rock drill feeding mechanism having improved transmission means between the power feeding element and the drill to be fed. A still further object is to provide an improved pneumatic feeding motor and improved flexible transmission means between the power feeding element and the drill to be fed. Yet another object is to provide an improved control means for the feeding means of a drill of the above character, and having incorporated therein improved fluid supply means whereby the fluid for operating the drill may flow through the feeding motor, thereby enabling automatic regulation of the feed by the flow of fluid to the drill to be fed. Still another object is to provide an improved mechanism for regulating the rate of feed automatically in accordance with the variations in the load on the drilling motor. A further object is to provide an improved mechanism for controlling the rate of feed automatically in accordance with the variations in the resistance to drill steel rotation. These and other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawings there are shown several forms and modifications which the invention may assume in practice.

In these drawings Fig. 1 is a side elevational view of one illustrative form of the improved rock drill.

Fig. 2 is an enlarged rear end elevational view of the drill shown in Fig. 1.

Fig. 3 is an enlarged cross sectional view taken substantially on line 33 of Fig. 1.

Fig. 4 is an enlarged central, longitudinally extending, vertical sectional view through the improved rock drill shown in Fig. 1, the view being taken substantially on line 4-4 of Fig. 2.

Fig. 5 is a somewhat diagrammatic sectional 50 view showing a portion of the improved control means.

Fig. 6 is a diagrammatic view showing two positions of the main control valve.

Fig. 7 is a diagrammatic view showing two positions of the auxiliary control valve.

Fig. 8 is a side elevational view, partly broken away in section, of the main control valve.

Fig. 9 is a side elevational view of the auxiliary control valve.

Fig. 10 is a detail sectional view taken substan- 3 tially on line l0-| 0 of Fig. 2.

Fig. 11 is a detail sectional view taken substantially on line I I-| I of Fig. 2.

Fig. 12 is a diagrammatic sectional view showing a modified form of control means.

Fig. 13 is a side elevational view of another illustrative form of the improved rock drill.

Fig. 14 is a central, longitudinally extending, vertical sectional view through the improved feeding means.

Fig. 15 is a cross sectional view taken substantially on line l5-l5 of Fig. 13.

Fig. 16 is a detail sectional view showing the feed control valve.

Fig. 17 is a view similar to Fig. 14, showing a 20 modified form of construction.

Fig. 18 is a cross sectional view taken on line Iii-l8 of Fig. 17.

In the illustrative embodiment of the invention shown in Figs. 1 to 11, inclusive, there is shown a rock drill of the mounted drifter type, although it will be evident that the various novel features of the invention may be incorporated in rock drills of various other types. The rock drill shown herein generally comprises a guide shell 1 adapted to be clamped in a usual saddle or trunnion support of a quarry bar or tripod mounting by which the drill is supported. Mounted on the guide shell I is the improved feeding mechanism, generally designated 2, and the rock drill hammer motor, generally designated 3.

The rock drill hammer motor 3 is of the pressure fluid actuated type of a standard and well known design, and comprises a motor cylinder 4 in which there is reciprocable a usual hammer piston adapted to actuate percussively a drill steel 5 supported in a usual manner within a front chuck housing 6. The cylinder 4 is provided with a rear cylinder head or head block I, and the motor parts, including the cylinder, chuck housing, and rear head, are held in assembled relation by usual spring-tensioned side rods 8. Pressure fluid is supplied to the hammer motor cylinder under the control of a usual throttle valve mechanism 9 having an operating handle l0. As is usual in rock drills of the type disclosed, means is provided for rotating the drill steel 5 as it is percussively actuated by the hammer piston. This rotationmeans comprises a ratchet and pawl mechanism having a spirally grooved rifle bar 2 slidingly interlocked with a usual rifle nut (not shown) fixed within the hammer piston so that when the hammer piston moves forwardly to effect its working stroke, the pawls 3 slipover the teeth of the ratchet 4 to permit the piston to strike an unimpeded blow on the drill. steel shank and when the hammer piston moves rearwardly, the pawl 3 engages the ratchet teeth to hold the rifle bar 2 against rotation so that a rotary motion is imparted to the hammer piston. The hammer piston has formed on its striking portion longitudinally extending straight grooves 5 slidingly interlocked with straight lugs formed on a chuck nut 6 threadedly secured to a chuck sleeve l rotatably mounted in the chuck housing 6. The chuck sleeve is connected to a driver member 8 likewise rotatably mounted in the chuck housing 6 and connected to the usual driver lugs on the drill steel shank. It will thus be seen that during the rearward piston stroke the rotary motion of the hammer piston is transmitted through the piston grooves 5 chuck nut 6 chuck sleeve I and driver member 8 to the drill steel 5.

Now referring to the improved feeding means 2, it will be noted that a guide shell I is provided with longitudinal guideways II in which 30 there are slidably guided lateral guides I2, herein formed integral with a sliding frame I3, on which the feed cylinder I4 of the feeding means is supported. The rear end of the feed cylinder I4 is closed by a rear head I5, herein preferably 35 formed integral with the rear head block I of the hammer motor, and this rear head I5 is formed with guides similar to the guides on the sliding frame I3 and likewise slidably engaging the guideways II on the guide shell I. The rear 40 head I5 is secured to the feed cylinder as by bolts I6, while the forward end of the feed cylinder is closed by a front head I'I secured to the feed cylinder, as by bolts I8.

The forward end of the cylinder 6 of the ham- 45 mer motor is provided with integral depending lugs Id at the sides thereof, engaging the top portion of the feed cylinder It, these lugs being provided with curved inner surfaces engaging the outer cylindrical surface of the feed cylin- .50 der, and being adapted to be secured to the feed cylinder, if desired.

Contained in the feed cylinder I4 for reciprocatory movement relative thereto is a feed piston 20, while formed below and parallel with 55 the bore of the feed cylinder is a bore 2| formed in a fluid sealing cylinder 22 integral with the feed cylinder it; and contained in the bore 2| is a sealing piston 23 arranged for reciprocatory movement. The pistons 29 and 23 are reversible 60 and are provided with suitable cup packings.

The feed piston 20 is connected in an improved manner to the rock drill hammer motor by means including improved flexible transmission means, this transmission means also con- 65 necting the feed piston to the sealing piston 23;

and in this instance this transmission means is in the form of a block chain 24, secured at 25 within the forward side of the feed piston 2|) and passing through a chamber 26 formed in 70 the front head I1 and guided by a chain idler 75 transmission means also includes a similar block chain 25 connected at 30 to the rear side of the feed piston 20 and passing rearwardly through a chamber 3| formed in the rear head I5, the chain passing around a chain drive sprocket 32 and forwardly through the bore of the sealing cylinder for connection at 33 to the rear side of the sealing piston 23. The sprocket 21 is arranged within the chamber 26 formed in the front cylinder head I1, and is journaled on a transverse shaft 34 suitably supported within 10 the cylinder head, while, as shown inFig. 3, the sprocket 32 is keyed to a transverse shaft 2-5 journaled Within bearing and sealing bushings 3'. supported within the rear cylinder head |5; and secured to the opposite ends of this shaft 15 35 and arranged externally of the head I5 at the opposite sides thereof are spur gears 37. These spur gears mesh with the teeth of racks 38 arranged longitudinally along and fixed to the opposite sides of the guide shell I. It will thus 20 be seen that when pressure fluid is supplied to one end or the other of the feed cylinder, the feed piston is moved axially within the feed cylinder, and this axial movement of the feed piston is transmitted through the flexible connec- 25 tions 2t, 29to the sprocket 32, thereby rotating the shaft 35 and causing the spur gears 37 to turn in one direction or the other along the racks 38, thereby moving the rock drill hammer motor in one direction or the other along the 30 guide shell. The sealing piston 23, moving in the bore 2| of the sealing cylinder and connected by the flexible connections 2 29 to the feed piston, prevents leakage of pressure fluid from the opposite ends of the feed cylinder, thereby 3 permitting the use of flexible transmission connections with their resultant advantages, while at the same time maintaining a fluid seal.

Now referring to the improved control means controlling the supply of pressure fluid to the feeding means and the hammer motor, it will be noted that arranged in a transverse bore 10 formed in the rear head block I is a rotary main control valve ll having an operating handle 62. Pressure fluid is supplied to the bore 43 of the valve through a pipe connection 44 leading to any suitable source of pressure fluid supply. Leading from the valve bore is a passage 45 communicating with a fluid supply chamber 46 formed in the rear head block I and through which pressure fluid flows through passages 4'1 and 48 under the control of the throttle valve mechanism 9 to the hammer motor 3. As shown most clearly in Fig. 5, also communicating with the valve bore and leading to the forward end of the feed cylinder I4, are parallel passages 49 and 50; while also communicating with the valve bore and leading to the rear end of the feed cylinder are parallel passages 5| and 52. The walls of the valve 4| are traversed by alined ports 53, while formed externally of the valve are circumferentially extending grooves 54 and 55. Arranged parallel with the valve bore 30 in the head block I is a valve bore 55 in which is rotatably mounted an auxiliary control valve 51 having an operating handle 58. As shown in Fig. 11, this handle 58 is always urged toward its neutral position by means of coiled springs 59, 59 interposed between lateral lugs 69 formed on the rear head block and the opposite sides of the handle. Pressure fluid is supplied to the bore 6| of this auxiliary valve from the bore 43 of the main control valve 4|, through a port 62 in the valve 4|, a circumferentially extending groove 63 on the valve 4|, a passage 64 in the head block, a circumferentially extending groove 65 on the valve 51, and a passage 66 in the valve 5'! connecting the groove 65 with the bore 6|. Communicating with the valve bore 56, as shown in Fig. 5, and leading to the passages 49 and 52 respectively, are passages 61 and 68'. 'Iraversing the walls of the auxiliary valve 51 is a passage 69, while formed on the exterior of the valve is a circumferentially extending groove 10, and communicating with this groove is a vent passage ii.

This improved control means for the hammer motor and feeding means operates in the following manner. When the main control valve 4| is in the position shown in Fig. 4, pressure fluid may flow through the valve bore 43, port 53, passage 45, supply chamber 46, and passages 41 and 48, under the control of the throttle valve mechanism 9, to the cylinder of the hammer motor 3, thereby effecting reciprocation of the hammer piston to actuate percussively and to rotate the drill steel 5. The auxiliary control valve 51 may then be rotated to the position a in Fig. 7, thus permitting pressure fluid to flow from the bore 6|, through the passage 69 to the passage 68 leading to the passage 52 communicating with the rear end of the feed cylinder, while the forward end of the cylinder is vented to atmosphere through passage 49, passage 61, groove ill on the valve 51, and vent passage ii. The pressure fluid acting on the rear face of the feed piston 25 moves the feed piston forwardly in the feed cylinder and, through the flexible connections 24, 29 and the gears 31 meshing with the racks 38, feeds the hammer motor forwardly along the guide shell I. When the auxiliary control valve 51 is rotated to the position b; in Fig. 7, the rear end of the cylinder bore is vented to atmosphere through passages 52 and 68, the groove 10 on the valve 51 and the vent passage 1|, while pressure fluid is supplied to the forward end of the cylinder bore from the bore 6| in the valve, through passage 69 and passages 61 and 49. The pressure fluid acts on the forward face of the feed piston 20, moving the latter rearwardly in the feed cylinder and, through the flexible connections and gears and racks, moving the hammer motor rearwardly along the guide shell i. It will thus be seen that when the valves are in the positions above described, the feeding means is operated in a novel manner to effect feed of the hammer motor forwardly or rearwardly along the guide shell.

When it is desired to effect automatic control of the feeding motor by the variations in the flow of pressure fluid to the hammer motor in accordance with load changes in the latter, the improved control means is operated in the following manner. When the main control valve 4| is rotated to the position a in Fig. 6, pressure fluid may flow from the bore 43 in the valve through passages 53, 53 and passages 49 and 52 leading to the opposite ends of the feed cylinder. When the valve is in this position, the groove 54 connects the passage 50 leading to the forward end of the cylinder bore with the fluid supply passage 45 for the hammer motor. When the throttle valve mechanism 9 of the hammer motor is in its closed position, the pressure fluid in the opposite ends of the cylinder bore at the opposite sides of the feed piston is balanced, and as the pressure areas at the opposite sides of the feed piston are equal, no feed is effected. When the throttle valve mechanism 9 of the hammer motor is turned into its open position, shown in Fig. 4, pressure fluid control valve 4| is rotated to position b in Fig. 6,2

may flow from the forward end of the feed cylinder bore through passage 50 and groove 54 on the valve 4|, to the fluid supply passage 45 for the hammer motor; and as the hammer motor operates, pressure fluid is taken through the pas- 5 sages above mentioned from the forward end of the feed cylinder, substantially reducing the pressure at the forward side of the feed piston, and as a result the line pressure acting on the rear pressure area of the feed piston overcomes the opposing reduced pressure on the front piston area and moves the piston forwardly to effect forward feed af the hammer motor along the guide shell. As the resistance to rotation of the drill steel varies in accordance with the requirements of the work, the rate of reciprocation of the hammer piston is correspondingly varied, and as a result, the flow of pressure fluid to the hammer motor is varied, the hammer motor as the hammer piston slows down using a considerably less amount of pressure fluid than when the hammer piston is running at a rapid rate. The variation in the flow of pressure fluid to the hammer motor effects a corresponding variation in the pressure in the feed cylinder so that the rate of 25 feed is automatically controlled in accordance with the load changes on the drilling motor. In other words, as the flow of pressure fluid to the hammer motor varies automatically in accordance with the load changes on the hammer motor, 30 the rate of feed correspondingly varies automatically in accordance with the variations of the pressure acting on one feed piston area opposing the line pressure acting on the opposed feed piston area. When the throttle valve mechanism 9 '85 is again turned into its closed position, the forward feed is stopped, due to the balancing of the pressures at the opposite sides of the feed piston. When reversal of the feed is desired, the main and at this time pressure fluid flows through the bore 43 in the valve, through passages 53, 53 and passages 50 and 5| leading tothe opposite ends of the feed cylinder. The passage 52 leading to the rear end of the feed cylinder is connected to the fluid supply passage 45 for the hammer motor through the groove 55. When the valve 4| is in this position and the throttle valve mechanism 9 for the hammer motor is closed, the pressure fluid flowing to the opposite ends of the feed cylinder at the opposite sides of the feed piston is balanced, so that the feed piston remains stationary. When the throttle valve mechanism 9 is turned to the position shown in Fig. 4, pressure fluid flows from the rear end of the cylinder bore through passages 52 and 45 to the hammer motor, and as the hammer motor operates, pressure fluid is drawn from the rear end of the feed cylinder, thereby substantially reducing the pressure acting on the rear pressure area of the feed piston, and as a result, the substantially line pressure acting on the forward piston area effects movement of the feed piston rearwardly, thereby feeding the hammer motor rearwardly along the guide shell Automatic control of the feed in accordance with load changes on the hammer motor is, of course, not possible during reverse feed since the hammer motor is not at that time operating to effect drilling.

It will be evident that the pressure fluid flowing from the feed cylinder to the hammer motor is substantially below line pressure, since a drop in pressure takes place within the feed cylinder due to the substantial flow therefrom to the hammer motor during running of the latter, and to 7 augment the supply of pressure fluid to the supply passage 45 of the hammer motor there is provided a separate source of fluid supply for this passage. In the modification shown in Fig.

Fl 12, the main control valve 4| has formed thereon a circumferentially extending groove I3 which communicates with the bore 43 of the valve through a passage I4. Communicating with this groove I3 and leading from the valve bore 40 to the supply passage 45 for the hammer motor, is a passage l5 communicating with the passage 45 through a port I6. This passage I5 may be opened or closed at will by a rotary valve 11 arranged in a bore I8 formed in the rear head block I and having a passage. 19 traversing the same.

When the valve 11 is in the position shown in Fig. '12, the auxiliary supply of pressure fluid to the supply passage 45 is cut off; and when the valve H is rotated to connect the passage I9 with the passage I5, pressure fluid may flow from the bore 43 of the valve 4I through passage 14, groove I3, passage I5 and port 16.

By suitable adjustment of valve 11, the pressure supply to the motor and the differential feeding pressure can be varied and the former increased for example with perhaps a diminution of the feeding pressure. It is to be understood that the modification of Fig. 12 is by no means necessary for satisfactory operation.

1 In the other illustrative embodiment of th invention, shown in Figs. 13 to 16, inclusive, the rock drill is generally similar to that shown in Fig. l, but in this instance is provided with a modifled'form of feeding means. The hammer motor 4 has formed integral therewith a sliding frame 8! having longitudinal guideways 82 slidably mounted on lateral guides 83 herein formed integral with a feed cylinder 84. This feed cylinder is provided with a usual swivel plate 85, fsimilar to the swivel plate in the form of the invention above described. Secured by bolts 86 to the feed cylinder is a rear head 81, while similarly secured to the forward end of the feed cylinder is a front head 88. Reciprocable in the 4 5 bore of the feed cylinder 84 is a feed piston 89, while reciprocable in a parallel bore 90 forming a sealing cylinder 9I integral with the feed cylinder along the upper side thereof, as shown in Fig. 14, is a sealing piston 92. The opposite sides of the feed piston 89 are connected by flexible elements, in the form of block chains 93 and 94, to the opposite sides of the sealing piston 92, these chains being guided by sprockets 95 and 96 journaled within the heads 81 and 88 of the feed cylinder in a manner similar to that above described in the preferred form of the invention. Inthis instance, the front guide sprocket 96 is keyed to a transverse shaft 9'! journaled within the front cylinder head 88 and having fixed thereto gears 93 meshing with the teeth of racks 99 formed on the opposite sides of the guide shell directly beneath the guides 82, 82. The transverse shaft 91 is suitably sealed against leakage through its bearing, as also is the shaft for sprocket 95. These shafts in this form, as well as the shafts of the earlier described form, may

have glands about them if desired.

In the modification shown in Figs. 1'7 and '18 the block chains are supplanted by cables or wire ropes I09 and NH, the cable l0I being coiled or snubbed about a drive pulley I02, while the cable I00 is guided by an idler sheave I03. In this form of the invention,the cable I00 is connected to the sealing piston I04 by a coiled spring I05, this coiled spring acting to maintain the cables I00, IOI at all times taut, so that as the feed piston 89 is reciprocated the pulley I02 is rotated, thereby-to effect rotation of the spur gears 93 in the manner above described.

Pressure fluid is supplied, in the modification of the invention shown in Figs. 13 to 18 inclusive to the hammer motor through a pipe connection I06 under the control of the throttle valve mechanism 9. Formed transversely in the rear feed cylinder head 81 is a valve receiving bore or chest I01 containing a rotary control valve I08 having an operating handle I09, and pressure fluid is supplied to the bore H0 of this valve through a flexible hose connection IiI connected by a T II 2 to the hammer motor supply connection I06. As shown most clearly in Fig. 16, the walls of the valve I08 are traversed by passages I I3 and I I4, while communicating with the valve receiving chest and leading to the opposite ends of the feed cylinder are fluid supply passages H5 and H6, the passage II5 leading to the rear end of the feed cylinder, and-the passage I I6 leading to the front end thereof. Also formed in the valve is a vent passage I I1. When the valve I08 is rotated to bring the passage H4 into communication with the forward feed passage H6, and the reverse feed passage I I5 in communica tion with the vent passage Ill, pressure fluid is supplied through the bore H9 of the valve and through passages H4 and lit to the forward end of the cylinder bore, the pressure fluid acting on the forward pressure area of the feed piston moving the latter rearwardly and, through the flexible connections and gears and racks, feeding the hammer motor forwardly along the guide shell. When the valve I08 is turned to bring the passage H3 into communication with the reverse feed passage II 5 and the forward feed passage 3 I6 in communication with the Vent passage II'I, pressure fluid flows through the reverse feed passage H5 to the rear end of the cylinder bore, the pressure fluid acting on the rear pressure area of the piston moving the latter forwardly and, through the flexible con nections and gears and racks, feeding the hammer motor rearwardly along the guide shell. As in the preferred form of the invention, during the feeding movement of the feed piston the sealing piston maintains the opposite ends of the feed cylinder sealed, thereby eliminating fluid leakage while permit-ting the use of flexible transmission connections. Vent passage I I! leads to and communicates at all times with a vent groove H8 in transverse planes spaced from passages H5 and As a result of this invention it will be noted that an improved rock drilling mechanism is provided, wherein in some forms the drilling motor is dependent upon the feeding motor for its source of actuating pressure, so that the feeding motor is controlled automatically by the fluid requirements of the drilling motor. It will further be noted that improved auxiliary means is provided for supplementing the supply of pressure fluid conducted from the feeding motor to the drilling motor, thereby to maintain the drilling motor fluid supply substantially up to line pressure. It will further be evident that by the provision of the particular transmission connections between the power feeding element of the feeding motor and the drill to be fed, the entire drilling mechanism is rendered extremely compact longitudinally, while by the provision of the sealing means associated with the transmission means, fluid leakage from the feeding motor is reduced to a minimum. These and other uses and advantages of the improved rock drilling mechanism will be clearly apparent to those skilled in the art.

While in this application there are described several forms and modifications of the invention, it will be understood that these forms and modifications are shown for purposes of illustration only, and that the invention may be further modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drilling mechanism, a rock drill, and means for feeding the rock drill comprising a feed cylinder arranged in parallel side by side relation with said rock drill, a feed piston recip-' rocable therein, flexible transmission means connected to said piston for actuation by the latter, rotatable means actuated by said flexible means, a rotatable feeding element actuated by the rotary motion of said rotatable means, and a cooperating feeding element with which said rotatable feeding element engages and relative to which said rotatable feeding element is bodily movable.

2. In a rock drilling mechanism, a guide shell, a rock drill movable longitudinally relative to said guide shell, and means for feeding and guiding said rock drill longitudinally relative to said guide shell comprising a feeding motor arranged in parallel side by side relation with and supporting said rock drill and mounted to move longitudinally relative to said guide shell with said rock drill, said feeding motor having a power movable element, and means including a stationary feeding element secured on the guide shell and a movable feeding element engaging said stationary element, and flexible transmission connections between said power movable element and said movable feeding element.

3. In a rock drilling mechanism, a guide shell providing longitudinal guideways, a rock drill, and means for feeding and guiding said rock drill longitudinally relative to said shell along said guideways including a feed cylinder mounted on said shell to move with said rock drill, a feed piston contained in said cylinder and reciprocable relative to said cylinder and said shell, and transmission connections between said reciprocable feed piston and said shell including a feeding element movable with the rock drill and feed cylinder, and a cooperating stationary feeding element on said guide shell whereby forward movement of said feed piston in said feed cylinder effects forward movement of said feed cylinder and rock drill relative to said shell.

4. In a rock drilling mechanism, in combination, a rock drill, a support providing longitudinal guiding means along which said rock drill is guided, and means for feeding said drill along said support comprising a reciprocable feed cylinder movable relative to said support, means for operatively connecting said cylinder to said drill, a feed piston movable with said feed cylinder and reciprocable relative thereto, and means actuated by said feed piston upon movement of the latter relative to said cylinder to effect movement of said cylinder relative to said support, thereby to effect'feed of the rock drill.

5. In a rock drilling mechanism, a rock drill, a guide shell, and means for feeding and guiding said rock drill longitudinally relative to said shell including a feed cylinder mounted on said shell and with which cylinder the rock drill moves during feed of the latter, said rock drill and said feed cylinder arranged in parallel side by side relation on said shell, a feed piston reciprocable in said feed cylinder, and operative feeding connections between said piston and theshell including a rotatable feeding element mounted to move with the drill relative to said shell during feed, and a cooperating element secured to said shell.

6. In a rock drilling mechanism, a pressure fluid actuated drilling motor, a pressure fluid actuated feeding motor for said drilling motor including a cylinder extending in the direction of motor feed and a feed piston reciprocable therein, means for operatively connecting said feed piston to said drilling motor, means for supplying pressure fluid to the opposite ends of said cylinder to act on the opposite sides of said feed piston to balance the latter, and means for supplying pressure fluid from one end of said feed cylinder at one side of said feed piston to said drilling motor to unbalance the pressures acting on said piston.

7. In a rock drilling mechanism, a guide shell providing longitudinal guideways, a rock drill,

and means for feeding and guiding said rock drill longitudinally relative to said guide shell along said guideways including a pressure fluid actuated feeding motor having a power feeding element, said feeding motor arranged in parallel side by side relation with said rock drill on said guide shell, flexible elements connected to said power feeding element of said feeding motor, elements mounted to move with said rock drill for guiding said flexible elements and actuated by the latter, a feeding element rotatable by one of said guiding elements, and a feeding element secured to said guide shell and with which said rotatable feeding element cooperates.

8. In a rock drilling mechanism, a rock drill, and means for feeding the rock drill including a feed cylinder arranged in parallel side by side relation with said rock drill, a piston reciprocable in said cylinder, a flexible transmission connection actuated by said feed piston, a rotatable element actuated by said flexible connection, and means rotated by said rotatable element and means with which said latter means cooperates and relative to which said rotatable means is rotatable to effect drill feed.

9. In a rock drilling mechanism, in combination, a rock drill, guiding means therefor, and means for feeding the rock drill along said guiding means comprising a feed cylinder arranged in parallel side by side relation to said rock drill, a feed piston reciprocable in said cylinder, and means for transmitting the motion of the feed piston to the rock drill comprising a flexible transmission connection actuated by said feed piston, cooperating toothed feeding elements, one rotatable relative to the other, and said other element stationary as regards bodily movement relative to said guiding means and means actuated by said flexible connection for effecting rotation of said rotatable feeding element relative to said other feeding element, rotation of said rotatable feeding element relative to said other feeding element effecting bodily movement of said rotatable element therealong.

10. In a rock drilling mechanism, a pressure fluid actuated hammer motor including a hammer piston for percussively actuating a drill steel, drill steel rotation means operated by said hammer piston, a pressure fluid actuated feeding motor for said hammer motor, means for supplying pressure fluid to said feeding motor, and means for supplying operating pressure fluid from said feeding motor to said hammer motor to maintain the latter in operation, the resistance to drill steel rotation varying the rate of reciprocation of said hammer piston, the flow of pressure fluid to said hammer motor varying automatically in accordance with the resistance to drill steel rotation, and the connections of said means for supplying pressure fluid to said feeding motor and of said means for supplying operating pressure fluid from the feeding motor to the hammer motor so constructed and arranged that the effective feeding force varies automatically in accordance with the fluid flow from said feed cylinder to said hammer motor.

11. In a rock drilling mechanism, a guide shell having longitudinal guideways thereon, a feeding motor mounted on said guide shell for movement longitudinally along the shell guideways and including relatively reciprocable cylinder and piston elements, a rock drill mounted on said feeding motor for movement therewith, said feeding motor arranged in parallelism with the shell guideways and extending coextensively with said guide shell within the latter, and connections actuated by the element of said feeding motor which is reciprocable relative to the other element of said motor for feeding said motor and said rock drill longitudinally relative to the guide shell including a gear mounted on said feeding motor and a rack secured to the guide shell with which said gear meshes.

12. In a rock drilling mechanism, a pressure fluid actuated hammer motor having a reciprocating hammer piston for percussively actuating a drill steel, drill steel rotation means operated by said hammer piston, a pressure fluid actuated motor for feeding the hammer motor, and means for controlling the effective feeding force automatically in accordance with the resistance to drill steel rotation and for supplying operating pressure fluid to said feeding motor including passage means for supplying at least the main volume of hammer motor operating pressure fluid from said feeding motor to said hammer motor.

13. In a rock drilling mechanism, in combination, a pressure fluid actuated hammer motor having a hammer piston for delivering impact blows to a drill steel, means operated by said hammer piston for rotating the drill steel, a pressure fluid actuated reversible feeding motor for feeding the hammer motor in either of opposite directions and comprising a motor cylinder having a piston chamber and a reciprocable feed piston contained in said chamber, means for supplying pressure fluid to said piston chamber at the opposite sides of said feed piston, means for supplying pressure fluid from said piston chamber of said feeding motor selectively at one side or the other of said feed piston to said hammer motor to effect operation of the latter and said drill steel rotating means, the pressure fluid in said piston chamber at the opposite side of said feed piston acting on the latter to effect movement of said feed piston in one direction or the other relative to the motor cylinder.

14. In a rock drilling mechanism, a guide shell providing a guideway, a rock drill supported on the shell guideway for movement therealong, and means for feeding said rock drill along said shell guideway including a feeding motor arranged beneath said rock drill in parallel side by side relation therewith and guided for movement with said rock drill along the shell guideway, said motor having a power feeding element movable along the guide shell as feeding takes place, and transmission connections between said power feeding element and the guide shell for moving said motor and drill along said shell.

15. In a rock drilling mechanism, a guide shell providing a guideway, a rock drill supported on the shell guideway for movement therealong, and means for feeding said rock drill along said shell guideway including a feeding motor arranged beneath said rock drill in parallel side by side relation therewith and guided for movement with said rock drill along the shell guideway, said motor having a power feeding element, transmission connections between said power feeding element and the guide shell including rotatable feeding means mounted to move with the rock drill and feeding motor, and a stationary feeding element secured to the guide shell and with which said rotatable feeding means engages.

16. In a rock drilling mechanism, a guide shell providing a guideway, a feeding motor guided for movement bodily along said shell guideway, said motor having a power operated element movable along the guide shell as feeding takes place, a rock drill mounted on and supported by said feeding motor for movement bodily therewith, said feeding motor located beneath said rock drill and said feeding motor and said rock drill arranged in parallel side by side relation, and means operated by said power operated motor element for feeding said motor and rock drill bodily along said shell guideway.

17. In a rock drilling mechanism, a pressure fluid actuated hammer motor having a reciprocating hammer piston for percussively actuating a drill steel, drill steel rotation means operated by said hammer piston, pressure fluid actuated feeding means for feeding the hammer motor including a power feeding element, means for supplying pressure fluid to the opposite sides of said power feeding element to effect balancing of the latter, and means for controlling the effective feeding pressure automatically in accordance with the resistance to drill steel rotation including means for supplying pressure fluid from the feeding motor at one side of said power feeding element to the hammer motor to effect operation of the latter, the flow of pressure fluid from said feeding motor at said side of said power feeding element resulting in a reduced efiective pressure at said side of said feeding element so that the pressure at the other side thereof effects feed of the hammer motor.

18. In a rock drilling mechanism, a pressure fluid actuated hammer motor having a reciprocating hammer piston for percussively actuating a drill steel, pressure fluid actuated feeding means for feeding the hammer motor including a power feeding element, means for supplying pressure fluid to the opposite sides of said power feeding element to effect balancing of the latter, and means for controlling the effective feeding pressure automatically in accordance with the changes in load on said hammer motor including means for supplying pressure fluid from the feeding motor at one side of said power feeding element to the hammer motor to effect operation of the latter, the flow of pressure fluid from said feeding motor at said side of said power feeding element resulting in a reduced effective pressure at said side of said feeding element so that the pressure at the other side thereof effects feed of the hammer motor, the flow of fluid from said feeding motor to said hammer motor varying automatically in accordance with the changes in load on the hammer motor.

19. In a rock drilling mechanism, a guide shell, a rock drill supported for movement longitudinally of said guide shell, and means for feeding the rock drill longitudinally of said guide shell including a feed cylinder arranged in parallel side by side relation with said rock drill, a piston reciprocable in said cylinder, a stationary feeding element secured to the'guide shell, a rotatable feeding element engaging said stationary feeding element and movable bodily relative thereto, and connections between said piston and said rotatable feeding element for rotating the latter.

20'. In a rock drilling mechanism, a guide shell, a rock drill supported for movement longitudinally of said guide shell, and means for feeding the rock drill longitudinally of said guide shell including a feed cylinder arranged in parallel side by side relation with said rock drill, a feed piston reciprocable in said cylinder, rotatable guides journaled at the ends of said feed cylinder, a stationary feeding element fixed to the guide shell, a rotatable feeding element engaging said stationary feeding element, flexible elements connected to and actuated by said piston and guided by said rotatable guides, and a connection between one of said rotatable guides and said rotatable feeding element, rotation of said guide and a connection between said piston and saidv rotatable feeding element and by which the latter is rotated.

22. In a rock drilling mechanism, a guide shell, a rock drill guided for longitudinal movement along said guide shell, and means for feeding said rock drill longitudinally relative to said guide shell including a feed cylinder stationary with respect to said guide shell, a feed piston reciprocable in said cylinder, a feeding element fixed to said rock drill for movement longitudinally therewith, a rotatable feeding element engaging said feeding element, rotatable guides journaled at the ends of said feed cylinder, flexible elements connected to said piston and guided by said r0- tatable guides, said flexible elements rotating said guides as they are actuated by said piston, and a connection between one of said rotatable guides and said rotatable feeding element, rotation of said latter guide effecting rotation of said feeding element.

23. In a hole forming mechanism, in combination, a pressure fluid actuated hammer motor for percussively actuating a hole forming implement, reversible pressure fluid actuated feeding means for feeding said hammer motor forwardly and rearwardly to move said implement toward and from the work comprising a reversible feeding motor arranged wholly in laterally offset relation to said hammer motor and having a motor chamber, means for controlling the supply of pressure fluid to said motor chamber, and means for effecting operation of said hammer motor during both forward and rearward feeding movemerits thereof embodying means for supplying at least the major portion of the operating pressure fluid to said hammer motor from said motor chamber.

24. In a hole forming mechanism, a pressure fluid actuated motor for percussively actuating a hole forming implement, reversible pressure fluid actuated feeding means for feeding said hammer motor forwardly and rearwardly to move said implement toward and from the work comprising a reversible feeding motor having a motor chamber, means for controlling the supply of pressure fluid to said motor chamber, and means for effecting operation of said hammer motor during both forward and rearward feeding movements thereof embodying means for supplying pressure fluid to said hammer motor from the portion of said motor chamber of said feeding means opposite to that within which pressure fluid is acting to provide the feeding force.

25. In a hole forming mechanism, in combination, a pressure fluid actuated hammer mechanism for percussively actuating a hole forming implement, a pressure fluid actuated feeding motor arranged in parallel offset relation with said, hammer mechanism for feeding the latter for-- wardly to move said implement toward the work and rearwardly to move said implement from the work, said feeding motor having a motor chamber containing a movable motor element, means for sup-plying pressure fluid to said motor chamber to effect operation of said feeding motor in either direction, and means for supplying pressure fluid from said motor chamber to said hammer mechanism during either direction of feed in suflicient quantity to effect and maintain sustained operation of said hammer mechanism.

26. In a rock drill, in combination, a guide shell providing a longitudinal guideway, a feeding motor unit comprising cooperating relatively movable, cylinder and piston motor elements, one of said motor elements constituting a power movable element, said feeding motor unit guided on said guide shell for bodily movement longitudinally along the shell guideway, a drilling motor mounted on said feeding motor unit, said drilling motor and feeding motor unit arranged in parallel side by side relation on said guide shell, and connections between said power movable element of said feeding motor unit and said guide shell for feeding both said feeding unit and said drilling motor bodily along the shell guideway.

27. In a hole forming mechanism, in combination, a pressure fluid actuated hammer motor having a hammer piston for delivering impact blows to a hole forming implement, a pressure fluid actuated reversible feeding motor for feeding said hammer motor in either of opposite directions and comprising a motor cylinder having a piston chamber and a reciprocable feed piston contained in said piston chamber, means for supplying pressure fluid to said piston chamber at the opposite sides of said feed piston, and means for supplying pressure fluid from said piston chamber selectively at one side or the other of said feed piston to said hammer motor to effect operation of the latter, the pressure fluid in said piston chamber at the opposite side of said feed piston acting on the latter to effect movement of said feed piston in one direction or the other relative to said motor cylinder.

28. In a hole forming mechanism, in combination, a pressure fluid actuated hammer motor having a reciprocatory hammer piston for percussively actuating a hole forming implement,

pressure fluid actuated feeding meansv for feeding said hammer motor including a power feeding element, means for supplying pressure fluid concurrently to the opposite sides of said power feeding element to effect balancing of said feeding element, and means for effecting feed and for controlling the rate of feed in accordance with changes in load on said hammer motor including means for supplying pressure fluid from the feed- I ing motor at one side of said power feeding element to said hammer motor to effect operation of the latter, the flow of pressure fluid from said feeding motor at said side of said power feeding element resulting in a reduced effective pressure at said side of said feeding element so that the pressure at the other side thereof effects feed of said hammer motor, the flow of fluid from said feeding motor to said hammer motor varying automatically with changes in load on said hammer motor.

29. In a hole forming mechanism, in combination, a pressure fluid actuated motor for actuating a hole forming implement, a pressure fluid actuated feeding motor for said implement actuating motor including a feed cylinder having a bore and a feed piston reciprocable therein, means for supplying pressure fluid to the opposite ends of said feed cylinder to act on the opposite sides of said feed piston, means for supplying pressure fluid from one end of said feed cylinder bore at one side of said feed piston to said implement actuating motor to effect operation of the latter, and means for augmenting the supply of pressure fluid from said feeding motor to said implement actuating motor; a

30. In a hole forming mechanism, in combina tion, a pressure fluid actuated motor for actuating a hole forming implement, a pressure fluid actuated feeding motor for said implement actuating motor and having a power feeding element,

means for supplying pressure fluid concurrently to the opposite sides of said power feeding element to effect balancing of the latter, and means for supplying pressure fluid from said feeding motor at one side of said power feeding element to said implement actuating motor to effect operation of the latter, thereby to eifect an unbalanced pressure at one side of said power feeding element.

31. In a rock drilling mechanism, in combination, a pressure fluid actuated hammer motor, a pressure fluid actuated feeding motor for said hammer motor comprising a motor cylinder having a piston chamber and a reciprocable feed piston contained in said chamber, means for supplying pressure fluid to said piston chamber at the opposite sides of said feed piston, means including a supply connection between said piston chamber at one side of said feed piston and said hammer motor for supplying to the latter from said piston chamber at least the major portion of the operating pressure fluid utilized by said hammer motor during drilling, the pressure fluid in said piston chamber at the opposite side of said feed piston acting on the latter to effect movement of said feed pistonrelative to said motor cylinder, and means for varying the ratio of the pressure of the fluid flowing to said hammer motor to the pressure of the fluid in said piston chamber at said first mentioned side of said piston to vary the rate of feed.

32. In a rock drilling mechanism, in combination, a pressure fluid actuated hammer motor having a reciprocatory hammer piston for delivering impact blows to a drill steel, means operated by said hammer piston for rotating the drill steel, a pressure fluid actuated feeding motor for feeding said hammer motor comprising a motor cylinder having a piston chamber and a reciprocable feed piston contained in said chamber, means for supplying pressure fluid to said piston chamber at the opposite sides of said feed piston, and means for supplying the entire quantity of operating pressure fluid utilized in running said hammer motor during drilling from said piston chamber, from the portion thereof at one side of 4!) said feed piston, the pressure fluid in the piston chamber at the opposite side of said feed piston acting on the latter to effect movement of the feed piston relative to the motor cylinder.

ELMER G. GARTIN. 

